Method and apparatus for the production of crimped yarns



Aug. 6, 1968 l. BALASSA 3,395,524

METHOD AND APPARATUS FOR THE PRODUCTION OF CRIMPED YARNS Filed July 28,1966 6 Sheets-Sheet 1 Fig. i

6, 1968 1. BAILASSA 3,395,524

METHOD AND APPARATUS FOR THE PRODUCTION OF CRIMPED YARNS Filed July 28,1966 5 Sheets-Sheet 2 Fig. 2

Aug. 6, 1968 l. BALASSA 3,395,524

METHOD AND APPARATUS FOR THE PRODUCTION OF CRIMPED YARNS Filed July 28,1966 3 Sheets-Sheet 3 United States Patent 3,395,524 METHOD ANDAPPARATUS FOR THE PRO- DUCTION 0F CRTMPED YARNS Imre Balassa, Buhl,Baden, Germany, assignor to Zinser- Textilmascliinen Gesellschaft mitbeschrankter Haftung, Ebersbach an der Fils, Germany, a German companyFiled July 28, 1966, Ser. No. 568,564 Claims priority, applicationGermany, July 28, 1965, R 83,006 18 Claims. (Cl. 5734) ABSTRACT OF THEDISCLOSURE The production of crimped yarns in which at least twoseparate yarns are fed under tension to a common twisting zone whereinthe yarns are twisted together. After a heat setting of the false twistproduced, the yarns are separated and drawn off under tension with equaldrawing off speeds. Each separated yarn runs through at least oneextension zone wherein the tension of the yarns are so controlled withintheir elastic range that when a relative difference in length of theyarns occurs, the tension of the shorter yarn is increased and that ofthe longer yarn decreased.

This invention relates to a method and an apparatus for the productionof crimped yarns.

The term crimped yarns is to be understood as including yarns which mayconsist of one or more endless filaments or of fibers. The yarn materialof such yarns consists at least in part of synthetic thermoplasticmaterials especially polyacrylonitriles, polyamides, polyesters and thelike.

More particularly, the present invention relates to a method of saidtype in which at least two separate yarns are fed by feeding means undertension to a common twisting zone, are twisted together in this twistingzone, and after heat-setting of the false twist thus produced, areseparated at a separating point and drawn off under tension by drawingoff means with equal speeds, and are subsequently spooled. In thismethod, the difficulty is encountered that the yarns in the rangebetween the feed ing means and the drawing-off means unavoidablyexperience different changes in length and consequently in tension,which if they are not constantly compensated for lead to stoppages andthread breakages.

In a known apparatus, it is provided for equalizing the unavoidabledifferences in tension of the threads that the lateral displacement ofthe point of separation arising with the different yarn tensions isdetected and the shorter thread is braked by means of a thread brakewhich can be activated or deactivated if the lateral displacement of thepoint of separation exceeds a predetermined limit. When the thread brakeis activated, the yarn tension drops in the zone between the point ofseparation and the thread brake whereby the equalization of tension isachieved. In addition, in the zone between the thread brake and thedraw-off means, a yiel'dingly mounted thread guide roller is providedwhich prevents the occurrence of excessive tensions in this zone. Thisapparatus has a number of disadvantages. Among other things, only anincomplete equalization of the tension can be achieved because thethread brake can only be either fully activated or deactivated. Further,since only the tension of one thread is affected, the equalization oflength takes place very slowly.

The object of the invention is the provision of a method of the typereferred to at the beginning of which the variations in length of thethreads can be equalized rap-idly and reliably. The present method forsolving this problem is characterized mainly in that the two separatedthreads ice each run through at least one extension zone in which thetensions of the yarns are so controlled or regulated within theirelastic range, that when a relative difference in length of the yarns toone another occurs, the tension of the shorter yarn is increased and thetension of the longer yarn is diminished. The expression relativedifference in length is to be understood as meaning the difference ofthe lengths of the two yarns in the range between the point ofseparation and the withdrawal point. Each relative length differencewhich occurs is rapidly equalized according to the invention by controlof the regulation of the tension of the threads in the extension zonesin that at each relative length difference which occurs, the tensions ofthe two yarns in the extension zone are varied in opposite directions.Preferably, it is provided that the difference in tension between thetwo yarns increases as the relative length difference increases, withthe variation in the tension difference occurring steadily.

The present method can, for example, be carried out in such a mannerthat a feeler for measuring the relative length difference is provided,and the signal of which is applied to a control or regulating appliancefor controlling the tension of the threads in the extension zones.

Since the tensions of the two threads when relative length differencesoccur are varied in opposite directions, in many cases the advantage ofincreasing the tension in the shorter thread in the extension zone canbe used for diminishing the tension of the longer thread by means of asuitable coupled means.

In a preferred further embodiment of the present method, it is providedthat the extension zones are associated with a common equalization zonein which the ratio of the tension of the yarns is approximately equal toone. The equalization member producing the equalization of the tensionsin the equalization zone may preferably be constructed in the form of afeeler for detecting the relative length dilference of the two yarns.

The apparatus for carrying out the present method can preferably beconstructed in such a manner that each of the two yarns bears on anon-driven coupled rotatable roller means defined by two co axiallyarranged conical rollers, the rollers being connected together forrotation and forming input rollers for the extension zone, and that athread guide device is provided through which the two threads independence on their relative lengths are so displaced along the axialdirection of the conical rollers that with increasing relative lengthdifference of the two threads the point at which the shorter thread runson to the coupled roller means is displaced in the direction of thereducing diameter of the conical rollers while the running on point ofthe longer thread is displaced in the direction of increasing diameterof the conical rollers. The apparatus is characterized by a particularlysimple and reliable construction. Also, it makes possible a verysensitive and continuous control of the tensions in the extension zonesso that any relative length differences which occur are constantly veryquickly equalized and large relative length differences cannot occur atall. The latter has among others the advantage that it is possible todispense with additional means for taking up relative length differencesexceeding the elastic range of the yarns. A particluar advantage of theapparatus consists also in, that it can be subsequently incorporatedwith little expense in practically all existing types of false twistcrimping machines. This applies also for the replacement of false twistrotating tubes by the present arrangement.

Further important objects and advantages of the invention will becomemore readily apparent to ersons skilled in the art from the followingdetailed description and annexed drawings and in which drawings:

FIGURE 1 is a plan view of a yarn separating appliance provided withwithdrawal rollers, according to the invention.

FIGURE 2 is a view in side elevation of the arrangement according toFIGURE 1, but with the withdrawal rollers omitted.

FIGURE 3 is a view on part elevation according to FIGURE 1, but in adifferent operative position.

FIGURE 4 is a plan view of another construction of the separatingappliance, according to the invention.

FIGURE 5 is a view'in side elevation of the apparatus according toFIGURE 4.

FIGURE 6 is a diagrammatic illustration of an apparatus for crimping theyarns.

In FIGURE 1 only the end section of a twisted yarn 1 is shown whereas inFIGURE 6 the supply zone and the twisting zone are illustrated in anexample. Yarns 6, 7 to be crimped are fed by feeding means defined bypairs of rollers 42, 45 with constant speed over guide rollers 43, 44,which are not driven, to a twisting zone in which the yarns betweenpoints 48 and 3 are twisted together and which is provided with aheating appliance 46 by means of which the false twist (crimping)applied to the yarns by the common twisting is heat set. The point 3 isthe separation point of the yarns which, after separation, run through astationary yarn guide 2 into a common equalization zOne where thetensions of the two yarns are equalized by means of a yarn guideappliance 50 (FIGURES 1 to 3) which is movable transversely to the yarnrun, and which consists essentially of the two parallelogram links 16and 17 which at one side have stationary pivots at 4a and 5a and attheir free ends have guide rollers 12 and 13 so that in this zone theratio of the tensions is equal to one. The parallelogram links 16 and 17are pivotally connected together by a coupling rod 18 and carrylaterally further guide rollers 14 and 15. In the directon of travel ofthe yarns behind guides 4 and 5, there is a coupled rotatable rollermeans having its axis of rotation transverse to the direction of the runof the yarn 1. The coupled roller means 10 has two symmetricallyarranged and constructed conical rollers 8, 9 which are in the form ofconical frustrums and which increase in diameter outwardly in relativelyoppm site directions The angle of the conical frustrums may be, forexample, about three degrees. The total length of both conical frustrumsis equal to the spacing of the guide rollers 12 and 13 together with alength section for the lateral displacement of the yarns, and therequired size of which can easily be determined by experiment. Beyondthe coupled rotatable roller 10 an ordinary withdrawal device 11provided with draw-off rollers 22 and 23 is arranged. The zones betweenthe conical rollers 8, 9 and the corresponding draw-off rollers 22, 23in this example correspond to the extension zones. According to FIGURES1 and 2, the course of the yarn between the twisting stretch and thedraw-off appliance is as follows. From the point of separation 3, theyarns 6 and 7 run through the yarn guides 2 consisting of hard metal orhard ceramic to the guide rollers 12, 13 and here they are deflected atright angles again parallel to the direction of travel of the twistedyarn. Then each of the yarns runs over the periphery of one of theconical frustrums 8 and 9 which, according to FIGURE 2, are surroundedby the yarns over an angle of more than 180. The conical frustroms 8 and9 preferably have a roughened surface or a suitable covering which has ahigh coefficient of friction with respect to the yarns. Together withthe large angle of contact this provides for reliable driving of thecoupled rotatable roller 10 by the travelling yarns whereby the relativemovement between the roller surface and the yarns and possible wear ofthe roller surface is avoided. From the upper side of the couplingroller 10 the yarns run over the guide rollers 14- and and over guidingpins 24 to the draw-off rollers 22 and 23 of the withdrawal or draw-offdevice 11, the draw-off speed of which is constant.

The apparatus operates as follows: the yarn guide 2 limits lateraloscillations of the thread in the twisting zone and provides for theyarns being separated smoothly and without damage. The tension of theyarns 6 and 7 deflected sideways from the yarn guide 2 is transmitted bythe guide rollers .12 and 13 in oppositedirections to the movable guides4 and 5. As long as the tensions in the two yarns are equal and theyarns between the point of separation 3 and draw-off points 52, 53(FIGURE 1), that is, the nips of the rollers 22, and 23 are of equallength, the guide rollers 12, 13 are in equilibrium in a symmetricalposition on both sides of=the yarn guide 2. The yarns 6 and 7 run overcorresponding portions of the conical frustrums 8 and 9 which are ofequal diameters. correspondingly, the speeds of travel of the two yarnsover the coupled rotatable roller means 10 are equal.

If now, for example, the tension of the yarn 6 increases owing toshortening as compared with the other yarn, a resultant force acts uponthe guides 4 and 5 which causes the parallelogram links .16, 17 to swingto the right with reference to FIGURE 1. Then the yarn 6 reaches a zoneof the conical frustrum 8 which is of smaller diameter while, for theyarn 7 on the conical frustrum 9, the opposite is true. In the extensionzones, the shorter yarn 6 is stretched since it tends to drive thecoupling roller with a higher speed than the longer yarn. The result isthat the shorter yarn 6 by reason of higher tension becomes additionallystretched in the extension zone while the stretching of the longer yarnis simultaneously diminished. In this way the relative length differencebetween the yarns is quickly equalized andthe yarn guide appliance 50returns to its central position. If the yarn 7 is shorter than theyarn6, the apparatus operates in the opposite manner as shown by theposition of the parallelogram links 16, 17 in broken lines in FIGURE 3.

The embodiment illustrated in FIGURES 4 and 5 differs from thatdescribed above in that yarn guide appliance 51 instead of a link guidefor transverse displacement of the yarns has a guiding device 40 whichis transversely displaceable by means of guide rails 20 or 21a and 21band corresponding rollers 25. The guide rails 20 and also 21a and 21bare united to form a rigid frame 19 on which the guide rollers 12, 13 aswell as the deflecting rollers 14, 15 are mounted. The rollers 25 arearranged in fixed positions and support the frame 19 in its horizontalposition so as to be displaceable transversely to the run of the twistedyarns. The coupled roller means 10 consists, as in the previous example,of two oppositely arranged frustrums 8 and 9 for which, however, acentral bearing in a bearing block 26 is provided. The arrangement andmode of operation of the various thread guiding members and the coupledroller means is the same as in the preceding embodiment. These parts aretherefore indicated by the same reference numerals as in FIGURES 1 to 3.

This invention is not to be confined to any strict conformity to theshowings in the drawings but changes or modifications may be madetherein so long as such changes or modifications mark no materialdeparture from the spirit and scope of the appended claims.

What I claim is:

1. Method of producing crimtped yarns in which at least two separateyarns are fed under tension to a common twisting zone, are twistedtogether in this zone and after heat-setting of the false twist therebyproduced are separated again at a separating point and are drawn offunder tension with equal drawing olf speeds, the improvernent comprisingrunning each of the two separated yarns at least through one extensionzone, controlling the tensions of the yarns in said extension zonewithin their elastic range, so that when a relative difference in lengthof the yarns occurs, the tension of the shorter yarn is increased andthe tension of the longer yarn is decreased.

2. Method as claimed in claim 1, further comprising increasing thedifference in tension between the two yarns as the relative lengthdiflerence increases, with the variation in the tension diflerenceoccurring steadily.

3. Method as claimed in claim 1, further comprising coupling thetensions of the yarns in the at least one extension zone with oneanother in such a manner that the tension of the longer yarn isdiminished by the shorter yarn while its tension is being increased.

4. Method as claimed in claim 1 further comprising establishing a commonequalizing zone through which the yarns run in association with said atleast one extension zone in which equalizing zone the ratio of thetension of the yarns is approximately equal to one.

5. A method as claimed in claim 4 in which the yarns run into theequalizing zone immediately after leaving the separating point and runinto the associated extension zone immediately after leaving theequalizing zone.

6. Method as claimed in claim 1, including drawing off the yarns fromthe at least one extension zone with constant and equal velocity.

7. An apparatus for producing crimped yarn including means for feedingat least two separate yarns under tension to means constituting a commontwisting zone wherein the yarns are twisted together, means for heatsetting the false twist produced in the twisting zone, means forseparating the yarns, means for drawing off the yarns under tension atequal drawing off speeds and means defining at least one extension zonethrough which each separated yarn runs, the improvement comprising anondriven rotatable coupled roller means on which each of the two yarnsbear, said rotatable coupled roller means comprising two coaxiallyarranged conical rollers, the two rollers being connected together forrotation and providing input rollers for the at least one extensionzone, and a yarn guide appliance through which the two yarns, inaccordance With their relative lengths, are so displaced in the axialdirection of the conical rollers that as the relative length diflerenceof the two yarns increases, the running point of the shorter yarn 0n theconical roller is displaced in the direction of decreasing diameter ofthe conical roller while the running on point of the longer yarn isdisplaced in the direction of increasing diameter of the concicalroller.

8. Apparatus as claimed in claim 7, in which the two yarns at leastpartly surround the corresponding conical rollers, with the angle ofcontact being greater than 180.

9. Apparatus as claimed in claim 7, in which the yarn guide appliancehas guiding elements for the two yarns which are arranged on a guidingdevice which is arranged to move transversely to the direction of travelof the yarn and the co-axial conical rollers being symmetrical withrespect to a common central plane perpendicular to the axis of theconical rollers, and increasing in diameter outwardly in oppositedirections.

10. Apparatus as claimed in claim 7 including a stationary yarn guide,whereby the yarns pass through said stationary yarn guide after leavingthe separating means.

11. Apparatus as claimed in claim 9, wherein said guiding elements arecomprised of guide rollers, whereby the yarns are firstly guided fromthe separating means outwardly at right angles and thereafter over saidguide rollers arranged symmetrically on both sides of the separatingpoint of the transversely movable yarn guiding device parallel to thedirection of travel of the twisted yarns and then to the conicalrollers.

12. Apparatus as claimed in claim 11, including deflecting rollers,whereby the yarns are guided by the guide rollers of the transverselymovable yarn guiding device around the conical rollers opposite to thedirection of travel of the yarns in the twisting zone to said deflectingrollers connected with the transversely movable guides and arranged infront of the separation point, and over these again in the direction oftravel of the yarn in the twisting zone to the drawing off means.

13. Apparatus as claimed in claim .12 in which the yarn guiding devicewhich is movable transversely to the direction of travel of the yarn inthe twisting zone is comprised of parallelogram links having oppositeends and stationary bearings at one end and a coupling rod, said linksbeing pivotally connected together by means of said coupling rod and onsaid opposite ends of said parallelogram links are mounted said guiderollers for the yarns which are arranged adjacent to the point ofseparation of the twisted yarns.

14. Apparatus as claimed in claim 13, in which the deflecting rollersfor the yarns disposed in front of the drawing off means are mounted onthe coupling rod.

15. Apparatus as claimed in claim 11 in which the guide rollers and thedeflecting rollers are arranged on a rigid frame mounted to bedisplaceable transversely to the direction of travel of the twistedyarns.

16. Apparatus as claimed in claim 15 including guiding rails and runningrollers, whereby said rigid frame is provided with said guiding railsand said running rollers and is arranged transversely to the twistingzone.

17. Apparatus as claimed in claim 7 in which the conical rollers of thecoupled rotatable roller means have a surface of a high coeflicient offriction with respect to the yarns running thereabout and are driven bythe yarns.

18. Apparatus as claimed in claim 11, in which the guide rollers arearranged on a rigid frame mounted to be displaceable transversely to thedirection of travel of the twisted yarns.

References Cited UNITED STATES PATENTS 7/1966 Kunzle et al. 5734 7/1966Kunzle et al. 5734

